The number of persons with an office workplace is steadily increasing. A large part of the workplace is exposed to the sun, which, besides desirable factors, may lead to undesirable glare effects. Distracting solar radiation can lead to a constant control of the shades and thus a frequent interruption of the working flow.
In general, glare situations can be annoying for persons in a room and can lead to a cutback in performance. For example, glare effect by a light source, such as the sun, can be annoying for a person reading, watching TV, working—especially when working on a desk and/or working on a computer-, eating, having a conversation with other persons or doing other activities.
In order to prevent light from falling through a transparent window on persons, in particular in the face, on the head or on the upper body of persons, which are in a room of a building, there are now some devices such as, for example, sun screens, sun blinds, blinds, dark adhesive films for transparent windows, electrically controlled shadeable windows and tinted windows.
Earlier devices have specific disadvantages, such as an unchangeable constant light damping, a complete darkening of the entire viewing area of a transparent window pane by coloring or tinting, or a complete optical suppression by the dimming means.
Darkening devices, such as blinds, cause the entire room to be darkened and not just the part that is relevant to the darkening. The contact to the outside is lost due to this darkening.
Often automatic blinds are raised in strong winds to prevent damage. For this reason, additional internal Venetian blinds are often used. The room heats up unnecessarily since the sun rays are blocked only after passing the window. In addition, the contact to the outside is lost.
Other darkening devices, such as electrochromic glazing, each darken an entire room, even when this is a disadvantage, for example during winter when warming by the sun is desired. Furthermore, electrochromic glazing has a considerable disadvantage with respect to the switching speeds; they switch very slowly. Furthermore, windows can only be darkened over a large area. For now, individual segments are not switchable, since switching signals with this technology would interfere with neighboring cells. A switching cycle takes up to 15 min. A selective fast darkening is thus not feasible.
Furthermore, darkening of the entire room (e.g. by blinds) can lead to a room-internal source of light, in particular for electric light, such as, for example, a light bulb, a fluorescent lamp, an uplight, a light-emitting diode lamp or an LED lamp or any other source of light, being switched on for better vision for the persons in the room, which would be avoidable with better use of the light from outside the building. Operating the indoor light source may require electrical power, which may involve costs.